First go into single user mode, at the time of booting, [ from grub menu you
can go in single user mode]
and after entering in single user mode check that xfs is on or not?
if not then start it.

/etc/rc.d/init.d/xfs start
then try to start gui mode, with command startx
now if this command will not start then try to recover xserver, with
following command.
just execute system-config-display
it will start one gui screen and will guide you to configure xserver for
your system.

thats it.
make appropriate change in /etc/inittab so after rebooting you can get gui
mode bydefault.
that is runlevel 5.